A liquid crystal display panel mainly comprises a TFT (Thin Film Transistor) array substrate and a color filter (hereinafter simply designated as CF) substrate which are molded in a registration manner, as well as liquid crystals and a driver module, wherein a turning direction of the liquid crystal molecules is controlled by means of a magnitude of an electric field so as to realize color display. In a process of the liquid crystal panel, a color filter layer mainly plays a role of color development.
In a process for producing the color filter substrate, various defect points, especially protrusion defects with heights, are inevitably caused, which easily result in poor bright points after the substrate registration. To eliminate the protrusion defects, the prior art generally employs a defect height measuring sensor to locate the protrusion defect points, and eliminates protrusions in a grinding manner. A disadvantage is that a measuring range of an existing defect height measuring sensor is relatively large, and a defect point locating precision is relatively poor. As a requirement for a resolution of a liquid crystal display in the market at present is increasingly higher, it is required that a pixel on the color filter substrate is designed smaller and smaller, and post spacers (hereinafter simply designated as PS) on the pixel are more and more intensive. These PSs are mainly used for support, and are configured to provide support between the TFT array substrate and the CF substrate to maintain an adequate space to be filled with liquid crystals. For a high-resolution display product, measuring the height of the defects is more inaccurate due to interference from the intensive PSs.